My son somehow managed to damage the gear assembly on his XUV 550. As I was looking for a replacement I saw this website and the rest is history.

I installed new gear assembly's which appear to be reinforced with a stainless steel plate on the outside (not sure why), after research on here, I chose to go with the HPI 1145 550 motors with heat sinks. I'll say this, I can see an instant speed increase and its significant for my children (3.5 and 2 years old). The motors stayed cool as they're set for 14.4 volts and I'm only running 12 volts right now. Plenty of torque and top speed compared to stock. I do have a 18v setup that I'm going to hold off on for awhile as my daughter fell out of the car yesterday, because my son who was driving, was driving like a 3 year old would.... or maybe I'll fabricate some seat belts...either way I love the new motors and they're worth every penny!!

Thanks for all the great information. I'm not really too handy and this site made the task very easy!! I will need to fabricate a space for the 18v when we're ready but I think it'll be easy and theres plenty of information on here about it.

Do you happen to still have the link to the motors / heat sinks & gear box? I'm only running 12V and my gear boxes are fine, as of now, but I think the motor are getting weak. the diver side motor tends to go in and out or just provide little power. I thought it was a wiring issue but I'm wondering if it's the motor now. (I've replaced them with the OEM type twice now)